This invention relates to a chain structure for bicycles, and more particularly, to a chain structure having inclined surfaces on the peripheries of inner and outer chain plates adapted to facilitate the engagement of the chain structure with sprocket teeth.
The evolution of bicycles, both in their function and appearance, have prompted changes in chain structure to accommodate various evolving requirements. Such a chain structure change is the formation of a pair of inclined surfaces at the center portion of each chain link to form a wider distance between opposed chain plates to facilitate engagement of sprocket teeth with the chain link, as shown in FIG. 6. This modification has provided more space for the engagement; however, when a switch in the sprocket wheel is prompted by a gear shift, the sprocket teeth will first engage the arcuate surface of a given chain plate, as shown in FIG. 7. Another change in chain structure has been to minimize the thickness and length of each chain plate in order to facilitate engagement with sprocket teeth. This change has increased engagement stability, but has also decreased the engaging area available to effect disengagement of the sprocket teeth from the chain structure.